Flash lamp



M. PlPKlN FLASH LAMP Filed Jan. 18, 1947 Feb. 14, 1950 inven'lor- Mor-vih' Pi His ATTor-neg.

Patented Feb. 14, 1950 UNITED STAT FLASH Marvin Pipkin, Cleveland Heights, Ohio, assignor to General Electric Company, a corporation or New York Application January 18, 1947, Serial No. 722,783

'3 Claims. (01. 67-3 1 vMy invention relates to flash lamps and more E particularly to that type of flash lamp used for photographic purposes which usually comprise a sealed transparent bulb containing a loosely arranged quantity of a readily combustible material together with a gas filling such as oxygen which, upon ignition of the lamp, enters into a reaction with the resulting emission of a momentary flash of actinic light.

The combustible materials usually employed in flash lamps of the above mentioned type generally consist of metal foil or fine wire or ribbon material loosely disposed throughout, and filling the bulbous portion of the bulb, usually in a crumpled manner. With such type flash lamps, a considerable portion of the combustible material rests in contact with the glass wall of the bulb. Consequently, when such a lamp is flashed, that portion of the combustible material in contact with the glass bulb burns very slowly, if at all, thereby resulting in the loss of actinic light which otherwise might be produced. Then, too, there is the possibility of the glass bulb cracking due to the contact thereof with the hot metal particles of the combustible material. Furthermore, in the case of the foil type lamps in particular, the handling of the thin foils and their insertion into the bulb is comparatively difficult and requires careful manual operations. Small portions or fragments of foil very often break off and have to be discarded, resulting in a considerable loss of such material which is very expensive.

One of the objects of my invention is to provide a flash lamp of the above type in which the combustible material is maintained in spaced relation to the glass bulb and out of contact therewith at all times.

Another object of my invention is the provision oi means to facilitate insertion of the combustible material into the bulb whereby such operation may be quickly performed and any broken pieces of combustible material effectively utilized.

A feature of the invention is the provision of a bag or pouch-shaped net made from glass wool, asbestos, or other suitable non-combustible material, in which the combustible material is enclosed and the whole then inserted within the bulb with the net arranged in a rumpled or irregular manner so as to substantially conform. to the contour of and engage the bulb only at spaced points.

Further objects and advantages of my invention will appear from the following description of a species thereof and from the accompanying drawing.

. 2 ,In the drawing, Fig. 1 is an elevation of a flash lamp comprising my invention, and Fig.2 is an elevation of a modified form of flash lamp according to the invention.

Referring to Fig. 1, the lamp according to the invention comprises a light-transmitting bulb I formed of glass or other suitable transparent ma.- terialand containing a small filament 2 the ends of which are connected to lead-in wires 3, 4 which extend through a stem 5 to a base 6 mounted on the neck of the bulb. The filament 2' is coated with a fulminating substance or primer I which serves as the-ignition means for the lamp. A disc 8, preferably of asbestos, is mounted on the stem 5 to shield the base end of the lamp from the heat of combustion and to prevent hot metal particles from coming in contact with the neck portion of the bulb.

Arranged within and substantially filling the active or bulbous portion of the bulb l is a loose filling of thin-sectioned solid (as distinguished from comminuted) combustible material 9 which may be either in the form ofleaf foil, or in the form of wire, ribbon, shredded foil or other filamentary character, of a suitable material such as aluminum or magnesium or alloys thereof. The combustible material 9 is enclosed withinva flexible pouch-shaped light-transmitting net It made of flne strands of non metallic material, preferably fine glass wool such as that com+ mercially known as Angels Hair, although as:- bestos .or any other suitable non-combustible material may be employed for this purpose. As shown in the drawing, the net l0 containing the combustible material 9 conforms substantially to the contour of the bulb wall and is arranged in a rumpled or irregular manner so as to contact the bulb wall only 'at spaced points and thus hold the combustible material away from the bulb wall. Being made of flne strands, the net It] has no appreciable cooling efiect on the enclosed combustible material 9 when the latter is ignited. To accomplish the objects of my invention, the openings in the net Ill should be small enough to prevent any portion of the enclosed combustible material 9 from projecting therethrough into contact with the bulb wall. However, where the net I0 is made of opaque material, the net openings should be large enough to permit transmission through the net of a sufficient amount or the light generated by the combustible material. In constructing the lamp according to the invention, the net Ill, which may be originally collapsed, is opened and the proper quantity of combustible material 9 stufied into the net "I,

after which the whole is then introduced into the bulb through the neck thereof. By the use of such a net l0, any loose pieces of combustible material which happen to break off are readily maintained in place by the net and can still be used in the lamp. Heretofore, such loose pieces had to be discarded for the reason that they might not remain in contact with the main body of combustible material and so would not be ignited at the flash. After the net ID with its enclosed combustible material 9 has been inserted and properly arranged within the bulb, the mount, comprising the stem 5, lead-in wires 3 4 and filament 2, is placed within the bulb and sealed to the neck thereof, with the lead-in wires 3, 4 projecting through the open lower end of the net Hi so as to position the ignition primer 1 within the mass of combustible material v9. The bulb is then exhausted and filled, through the exhaust tube H, with oxygen or other combustion-supporting gas to a suitable pressure. The *base 6 is then a-flixed to the bulb and the lead-in 'Wires '3, 4 connected to the terminals of the base.

The combustible material 9 may be all of one size '(i. e., of "the same thickness 'in the case of leaf foil or of thesame cross-sectional size in the case of wire or ribbon material) so as to possess the same combustion rate, or it maybe of different sizes or thicknesses so as to possess dif- Ierent combustion rates. In the latter case, the different sized combustible material may be arranged in the manner shown in Fig. 2, i. e., in entirely separate :masses '12, I 3 located in definite relatiohto the ignition primer 1 to produce special flash characteristics, such as disclosed in Oram Patent 2,334,155 wherein a mass of relatively coarse filamentary material is disposed withinthe upper portion of "the *bulb and a mass of rela tively fi-ne filamentary material is disposed within the lower portion of the bulb around the ignition primer to produce, on ignition, a prolonged flash of light suitable for use with cameras having fl ocal plane shutters. The use of an :enclos- 'ing net i i or the combustible material of such tocal plane type flash lamps is particularly advantageous in'that the net helps to maintain the two diffieren't masses I 2, 13 :of combustible material in their original prearranged relation with each other and with the primer, which relation must be maintained if the lamp is to perform the intended manner to produce a prolonged tight :flash. To more effectively assure the maintenance of such relation, thetwo dififerent masses l2, l3 of combustible material (Fig. 2) may, as shown, be enclosed in separate nets I 4 and [5, respectively, or only the coarse or the line mass of combustible material enclosed in a net H], with or without an enclosing net around the whole in either case.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A flash lamp comprising a light-transmitting bulb containing a combustion-supporting gas, a quantity of thin-sectioned solid combustible material loosely arranged within and sub 'stantially filling the active portion of said bulb, and a flexible net of fine strands of non-metallic non-combustible material enclosing said combustible material and substantially holding it out of contact with said bulb.

2. A flash lamp comprising a 1ight-transmit tin bulb containing a combustion-supporting gas, a quantity of thin-sectioned solid combustible material loosely arranged within and substantially filling the active portion of said bulb, and a flexible net formed of glass wool enclosing said combustible material and substantially hold ing it out of contact with said bulb.

3. A flash lamp comprising a light-transmitting bulb containin a combustion-supporting gas, a quantity of thin-sectioned solid combustible material loosely arranged within and substantially filling the active portion of said bulb. said combustible material comprising separate masses of material of diiierent combustion rates disposed in predetermined relation With each other within the bulb, and a non-combustible flexible light-transmitting net enclosing at least one of said masses of combustible mater'ial'to thereby hold the said masses in said predetermined relation.

MARVIN 'PIPKIN.

REFERENCES CITED The following references are of record in the the of this patent:

Great Britain .Apr. 29, 1937 

